Finding the Fourth Proportional to 1,381.37, 1,906.49 and 857.57

Step by Step Solution

1. Step 1: Write the proportion equation
   1,381.37 : 1,906.49 = 857.57 : x
2. Step 2: Convert to fraction form
   1,381.37/1,906.49 = 857.57/x
3. Step 3: Cross multiply
   1,381.37x = 1,906.49 × 857.57
4. Step 4: Simplify right side
   1,381.37x = 1,634,948.63
5. Step 5: Solve for x
   x = 1,634,948.63/1,381.37
6. Step 6: Final answer
   x = 1,183.57